The aim of the Clinical Core is to provide for the clinical needs of the proposed projects. This requires that each evaluation be conducted according to a standard protocol that is periodically modified in accordance with advances in the field. The initial assessment and six- month follow-up evaluations are standardized along lines recommended by the NINCDS-ADRDA study group.1 The specific aims of the Clinical Core are twofold: (1) to provide diagnostic services and screening evaluations for patients entering the research protocols. (2) to provide for the distribution of patients, control subjects, and clinical information to the proposed projects.